Ic/mA 3 Q1.66 Uce/V 5.4 12
IC?0,UCE?UCC?12V
UCE?0 IC?UCC12?mA?3mA
RC?RE2?2 UCE??12?(2?2)?1.66?V?5.4V 静态工作点合适，在小信号情况下不会产生失真。
习题15.6.1 在题15.6.1图的射极输出器中，已知RS?50?，RB1?100k?，
RB2?30k?，RE?1k?，晶体管的??50，rbe?1k?，试求Au，ri和ro。
+Ucc Rb1C1++ Rs+ Es-Ui Rb2T C2++ Re Uo--
习题图15.6.1
解：Au?(1??)RE(1?50)?1??0.98
rbe?(1??)RE1?(1?50)?1ri?RB1//RB2//?rbe?(1??)RE? ?100//30//?1?(1?50)?1? ?15.9k?
r0?RS//RB1//RB2?rbeR?r50?1000//RE?Sbe??21?
1???50习题15.6.2 两级放大电路如题图15.6.2（a）所示，晶体管的?1??2?40，
rbe1?1.37k?，rbe2?0.89k?。①画出直流通路，并估算各级电路的静态值（计算UCE1时
忽略IB2）；②画出微变等效电路，并计算Au1，Au2和Au；③计算ri和ro。
Ic1Β1Ib1Rbe1Ui Rb1 Rb2R``e1 Ib1Ib2 Rbe2++ Rc1Β2Ib2 Re2 RL Uo --
习题15.6.2图
解：①各级电路的静态值：
前级：UB?RB28.2UCC??20?3.98V
RB1?RB233?8.2RB?RB1//RB2?33//8.2?6.57k?
IB1?UB?UBE13.98?0.6??23?A
?1?RE??1)6.57?(1?40)(0.39?3)RB?(1??1)(REIC1??1IB1?0.92mA
?1?RE?2)?20?0.92?(10?0.39?3)?7.7V UCE1?UCC?IC1(RC1?RE后级：UCC?(IC1?IB2)RC1?UBE2?(1??2)IB2RE2
IB2?UCC?UBE2?IC1RC120?0.6?0.92?10??47?A
RC1?(1??2)RE210?(1?40)?5.1IE2?(1??2)IB2?(1?40)?47?1.93mA UCE2?UCC?IE2RE2?20?1.93?5.1?10.2V
若采用估算法，则：UB1?RB28.2UCC??20?3.98V
RB1?RB233?8.2IC1?IE1?IUB1?UBE13.98?0.61??1mA，IB1?C1??25?A
?1?RE??1RE3?0.39?140?1?RE??2)?20?1?(10?0.39?3)?6.6V UCE1?UCC?(RC1?REIC2?IE2?UCC?IC1RC1?UBE220?1?10?0.6??1.84mA
RE25.1IB2?IE21.84??45?A，UCE2?UCC?IC2RE2?20?1.84?5.1?10.6V， 1??21?40②微变等效电路如下图所示：
+20V Rc1 Rb1 33kΩ 10kΩC1++50uFT1 R``e1 0.39kΩT2C2+Ui 8.2kΩ Rb2 R`e1 3kΩ+ 50uF5.1kΩ+ RL Uo Re25.1kΩ Ce- 50uF-
习题15.6.2图
后级：
?2